Prior osteosynthesis-unlike osteotomy-raises revision risk after total knee arthroplasty, predominantly via periprosthetic infection.

Abstract

Previous knee surgery is discussed as a risk factor for total knee arthroplasty (TKA), yet most reports do not distinguish between osteotomy and osteosynthesis. The German Operationen- und Prozedurenschlüssel (OPS)-based classification was used to compare the impact of these procedures on implant survival, mortality and complications after primary TKA. Data from the German Arthroplasty Registry (2012-2024) were used. Patients with prior osteosynthesis (n = 10,078) and prior osteotomy (n = 96,782) were each 1:1 Mahalanobis-matched to controls without prior knee surgery (matching on age, sex, Elixhauser score, body mass index [BMI], fixation, arthroplasty type and bearing mobility). Primary endpoints were all-cause revision and mortality; secondary endpoints were periprosthetic joint infection (PJI), periprosthetic fracture and aseptic loosening. Kaplan-Meier with 95% log-log confidence intervals (CI) and log-rank tests were used; Cox proportional hazards models estimated hazard ratios (HRs). All-cause revision differed for osteosynthesis versus controls (log-rank p < 0.001) but not for osteotomy (p = 0.972). In Cox models, prior osteosynthesis was associated with a higher revision hazard (HR 1.81, 95% CI 1.52-2.15; p < 0.001). For osteotomy, no increased revision hazard was observed across age (<65/≥65 years) or comorbidity (Elixhauser < 3/≥3) strata. Mortality was higher after osteosynthesis (HR 1.48, 95% CI 1.34-1.64; p < 0.001), while osteotomy showed no overall increase; PJI occurred more often after osteosynthesis (HR 1.62, 95% CI 1.21-2.19). Periprosthetic fracture (HR 8.54, 95% CI 3.02-24.1) and aseptic loosening (HR 2.38, 95% CI 1.24-4.59) were likewise increased after osteosynthesis. Prior osteosynthesis increases revision risk after TKA-predominantly via infection-whereas prior osteotomy does not. These findings support extended perioperative infection workup, staged hardware removal when indicated and careful implant selection in patients with prior osteosynthesis; outcomes after osteotomy are comparable to primary osteoarthritis. Level IV, retrospective observational study.